15-deoxy-delta(12-14)-prostaglandin-j2 and Prostatic-Neoplasms

Fifteen-deoxy-Δ(12,14)-PGJ(2) (15d-PGJ(2)) is one of non-enzymatically converted metabolite from prostaglandin D(2) (PGD(2)). Anti-tumor effects of 15d-PGJ(2) in various tumors are partially known, but the detail of in vivo mechanisms of action is still unclear. In this study, we investigated the effects of 15d-PGJ(2) and PGD(2) on murine prostate cancer in vitro and in vivo. Murine prostate cancer cells RM9 were transfected with murine prostaglandin D(2) synthase (mPGDS) gene by using defective retrovirus vector, designated as RM9-mPGDS. In addition, RM9 was also transfected with only defective retrovirus vector, designated as RM9-EV and used as control in this study. The expression and production of the gene were confirmed by RT-PCR and ELISA, respectively. For in vivo study, RM9-mPGDS was injected into the back of C57BL/6 mice, then resulted tumor was used for pathological analysis 14days after the inoculation. Tumor cell apoptosis in the tissue was detected by TUNEL staining. Retrovirally transfected mPGDS in RM9 significantly induced apoptosis in vivo but not in vitro, by TUNEL staining and cell death ELISA, respectively. Our results strongly suggested that the apoptosis induced in RM9-mPGDS in vivo was probably achieved in tumor environment such as hypoxic condition. The introduction of PGDS gene into cancer cells might be a novel therapy against cancer.

Topics: Animals; Apoptosis; Cell Line, Tumor; Enzyme-Linked Immunosorbent Assay; Genetic Vectors; In Situ Nick-End Labeling; Intramolecular Oxidoreductases; Lipocalins; Male; Mice; Mice, Inbred C57BL; Prostaglandin D2; Prostatic Neoplasms; Retroviridae; Reverse Transcriptase Polymerase Chain Reaction; Transfection

The PPAR-gamma ligands, 15-deoxy-Delta(12,14)-prostaglandin J(2) and ciglitazone, and the PPAR-alpha ligand, WY-14643, were examined for their effects on proliferation and apoptosis of A375 melanoma, DU145 and PC3 prostate cancer, and MB-MDA-231 breast cancer. While 15-deoxy-Delta(12,14)-prostaglandin J(2) inhibited proliferation of A375 melanoma, ciglitazone was inactive against this and the other cell lines. Restriction of specific amino acids known to inhibit proliferation and induce apoptosis sensitized all cell lines to ciglitazone, and the combined effects were greater than the individual effects of either treatment. WY-14643 alone or in combination with amino acid deprivation was inactive. Normal fibroblasts were resistant to the treatments.

Topics: Amino Acids; Antineoplastic Agents; Apoptosis; Breast Neoplasms; Cell Line, Tumor; Cell Proliferation; Cell Survival; Dose-Response Relationship, Drug; Female; Humans; Hypoglycemic Agents; Immunologic Factors; Ligands; Male; Melanoma; Methionine; Phenylalanine; PPAR gamma; Prostaglandin D2; Prostatic Neoplasms; Thiazolidinediones; Tyrosine

Cyclopentenone-prostaglandin derivatives, including the peroxisome-proliferator activated receptor gamma (PPARgamma) ligand 15-deoxy-Delta12,14-prostaglandin J2 (15d-PGJ2), inhibit tumor cell growth in vitro and in vivo. As 15d-PGJ2 was found to stimulate the expression of vascular endothelial growth factor (VEGF) in endothelial cells, we investigated whether 15d-PGJ2 induces this angiogenic factor in the human androgen-independent PC 3 prostate and the 5637 urinary bladder carcinoma cell line. In PC 3 cells, 15d-PGJ2 caused a dose-dependent increase in VEGF mRNA expression, as determined by RT-PCR. Stimulation started after 6 h, and after 72 h, VEGF mRNA expression reached a maximum of 3.3+/-0.3 U, 4.4+/-0.3 U and 6.1+/-0.1 U with 1, 5 and 10 microM 15d-PGJ2, respectively. Between 12-72 h, VEGF protein production was stimulated by up to 2-fold with 5 and 10 microM 15d-PGJ2 as assessed by ELISA in PC 3 cell-conditioned medium. In 5637 cells, 15d-PGJ2 did not alter VEGF mRNA expression for up to 72 h. Thereafter, VEGF mRNA expression was transiently increased from 2.3+/-0.8 U in control cells to 4.6+/-0.5 U in 1 microM and 5.9+/-0.6 U in 5 microM 15d-PGJ2-treated cells. VEGF protein production was only moderately stimulated (1.7-fold). 10 microM 15d-PGJ2 had no effect on VEGF mRNA expression in 5637 cells, but effectively reduced viability in both cell lines. 15d-PGJ2 also increased PPARgamma mRNA expression in both cell lines. While in PC 3 cells, stimulation of PPARgamma mRNA expression occurred after 72 h, in 5637 cells, a transient stimulation took place after 6 h (4-fold). We demonstrated that 15d-PGJ2 induces VEGF in PC 3 and 5637 cancer cells. This might be important if PG-analogues are considered as antitumor agents.

Topics: Cell Survival; Endothelial Growth Factors; Humans; Immunologic Factors; Intercellular Signaling Peptides and Proteins; Ligands; Lymphokines; Male; Prostaglandin D2; Prostatic Neoplasms; Receptors, Cytoplasmic and Nuclear; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Time Factors; Transcription Factors; Tumor Cells, Cultured; Urinary Bladder Neoplasms; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factors

15-Deoxy-delta12,14-prostaglandin J2 (15d-PGJ2) is a highly specific activator of the peroxisome proliferator-activated receptor gamma (PPAR-gamma). We investigated the effect of 15d-PGJ2 on three human prostate cancer cell lines, LNCaP, DU145, and PC-3. Western blotting demonstrated that PPAR-gamma1 is expressed predominantly in untreated prostate cancer cells. Treatment with 15d-PGJ2 caused an increase in the expression of PPAR-gamma2, whereas PPAR-gamma1 remained at basal levels. PPARs alpha and beta were not detected in these cells. Lack of lipid accumulation, increase in CCAAT/enhancer binding proteins (C/EBPs), or expression of aP2 mRNA indicated that adipocytic differentiation is not induced in these cells by 15d-PGJ2. 15d-PGJ2 and other PPAR-gamma activators induced cell death in all three cell lines at concentrations as low as 2.5 microM (similar to the Kd of PPAR-gamma for this ligand), coinciding with an accumulation of cells in the S-phase of the cell cycle. Activators for PPAR-alpha and beta did not induce cell death. Staining with trypan blue and propidium iodide suggested that, although the plasma membrane appears intact by electron microscopy, disturbances are evident as early as 2 h after treatment. Mitochondrial transmembrane potentials are significantly reduced by 15d-PGJ2 treatment. In addition, treatment with 15d-PGJ2 resulted in cytoplasmic changes, which are indicative of type 2 (autophagic), nonapoptotic programmed cell death.

Topics: Cell Death; Cell Membrane; Cell Survival; Gene Expression Regulation, Neoplastic; Histocytochemistry; Humans; Male; Membrane Potentials; Microscopy, Electron; Mitochondria; Prostaglandin D2; Prostatic Neoplasms; Receptors, Cytoplasmic and Nuclear; S Phase; Transcription Factors; Tumor Cells, Cultured

The biological modifier delta12-prostaglandin J2 and related prostaglandins have been reported to have significant growth-inhibitory activity with induction of heat shock proteins (Hsps). Tumor-derived Hsps have been shown previously to elicit specific immunity to tumors from which they are isolated. In this study, 15-deoxy-delta12,14-prostaglandin J2 (15d-PGJ2)-induced Hsp70 was purified from transgenic adenocarcinoma mouse prostate cells (TRAMP-C2). It was then tested for its ability to activate specific CTLs and induce protective immunity against prostate cancer in C57BL/6 mice. Treatment of cells with 8.0 microM 15d-PGJ2 for 24 h caused significant induction of Hsp70 expression. The yield of Hsp70 purified from 15d-PGJ2-treated cells was 4-5-fold higher when compared with untreated TRAMP-C2 cells. Vaccination of mice with Hsps isolated from TRAMP-C2 cells elicited tumor-specific CTLs and prevented the growth of TRAMP-C2 tumors. These results indicate that the induced heat shock proteins may have promising applications for antitumor, T-cell immunotherapy. In particular, these findings have important implications for the development of novel anticancer therapies aimed at promoting an immune response to prostate tumors.

Topics: Adenocarcinoma; Animals; Cancer Vaccines; Dose-Response Relationship, Drug; HSP70 Heat-Shock Proteins; Immunity, Innate; Immunologic Factors; Male; Mice; Mice, Inbred C57BL; Mice, Transgenic; Prostaglandin D2; Prostatic Neoplasms; T-Lymphocytes, Cytotoxic; Tumor Cells, Cultured